Image reading apparatus

ABSTRACT

An image reading apparatus includes: a contact glass provided at an upper surface of a main body of the apparatus to set a manuscript thereon, an image sensor being positioned below the contact glass and having a reading surface on contact glass side for reading an image from the manuscript on the contact glass, a carriage supporting the image sensor accommodated in a sensor container formed to have a recess open to the contact glass side, a rail member slidably supporting the carriage, and a biasing member biasing the image sensor to the contact glass side via a biased portion adjacent to the reading surface of the image sensor. An upper end of the biasing member is positioned below the contact glass and above the lower surface of the image sensor.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority from Japanese Patent ApplicationNo. 2011-219220, filed on Oct. 3, 2011, the disclosure of which isincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an image reading apparatus which isconfigured to read an image from a manuscript on a contact glass by animage sensor contained in a carriage.

Description of the Related Art

Conventionally, as image reading apparatuses, so-called flatbed typeimage reading apparatuses have been known. Such an image readingapparatus has a contact glass at the upper surface of its main body forsetting a manuscript. The image reading apparatus is configured to readan image of the manuscript set on the contact glass by an image sensorprovided inside the main body. Then, the image sensor is installed on acarriage which is set to be slidable on a rail provided inside the mainbody. The image sensor is configured to slide along the rail togetherwith the carriage when reading the image of the manuscript.

The invention disclosed in Japanese Patent Application Laid-Open No.08-163291 is known as an invention with respect to such image readingapparatuses described above. In the image reading apparatus disclosed inJapanese Patent Application Laid-Open No. 08-163291, the image sensor isplaced on the carriage which is slidable along the rail. The imagesensor is biased upward toward the contact glass by springs providedbetween the lower surface of the image sensor and the upper surface ofthe carriage.

Here, in the image reading apparatus disclosed in Japanese PatentApplication Laid-Open No. 08-163291, the springs are provided betweenthe lower surface of the image sensor and the upper surface of thecarriage. Therefore, even if the springs are compressed to the limit,the springs still occupy a certain height. Therefore, the springs whichoccupy the certain height become an obstacle to the apparatusminiaturization which has been desired in recent years.

SUMMARY OF THE INVENTION

Accordingly, the present invention relates to image reading apparatuseswhich is configured to read an image from a manuscript on a contactglass by an image sensor contained in a carriage, and an object of thepresent invention is to provide an image reading apparatus capable ofbiasing the image sensor toward the contact glass by biasing means whilefacilitating miniaturization of the apparatus.

An image reading apparatus according to an aspect of the presentinvention includes a contact glass, an image sensor, a carriage, a railmember, and a biasing member, and is capable of reading an image from amanuscript set on the contact glass by sliding the image sensor, whichis accommodated in a sensor container of the carriage, together with thecarriage along the rail member. In the image reading apparatus accordingto the aspect of the present invention, because the biasing memberbiases the image sensor toward the contact glass via a biased portionadjacent to a reading surface of the image sensor which is accommodatedin the sensor container, the biasing member is not positioned between alower surface of the image sensor and a bottom surface of the sensorcontainer. By virtue of this, it is possible for the image readingapparatus to facilitate miniaturization of the apparatus in its verticaldirection. Further, because an upper end of the biasing member ispositioned below the contact glass and above the lower surface of theimage sensor, the image reading apparatus can reliably bias the imagesensor toward the contact glass by the biasing force of the biasingmember.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective external view of a multifunction apparatusaccording to a first embodiment of the present invention.

FIG. 2 is a plan view showing an inner structure of a scanner unit ofthe multifunction apparatus.

FIG. 3 is a plan view of an image sensor installed on a first carriageof the multifunction apparatus.

FIG. 4 is a perspective external view showing a structure of the firstcarriage.

FIG. 5 is a cross-sectional view of a holder member attached to thefirst carriage.

FIG. 6 is a perspective external view of the image sensor installed on asecond carriage according to a second embodiment of the presentinvention.

FIG. 7 is a cross-sectional view of a holder member attached to thesecond carriage.

FIG. 8 is a plan view of the image sensor installed on a third carriageaccording to a third embodiment of the present invention.

FIG. 9 is a plan view of the image sensor installed on a fourth carriageaccording to a fourth embodiment of the present invention.

FIG. 10 is a perspective external view of the image sensor installed ona fifth carriage according to a fifth embodiment of the presentinvention.

FIG. 11 is a cross-sectional view of a holder member attached to thefifth carriage.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinbelow, referring to the accompanying drawings, explanations willbe made in detail with respect to several embodiments in which an imagereading apparatus according to the present invention is embodied as amultifunction apparatus 1 having a scanner unit 10.

First Embodiment

First, referring to FIGS. 1 and 2, a schematic configuration of themultifunction apparatus 1 according to first embodiment will beexplained. In the following explanations, with the multifunctionapparatus 1 placed in a usable state as a reference, the up-downdirections are defined as shown in FIG. 1. The lower right side in FIG.1 is defined as the front side of the multifunction apparatus 1, and theupper left side in FIG. 1 is defined as the rear side of themultifunction apparatus 1. Further, with the multifunction apparatus 1viewed from the front side as a reference in left-right direction, thelower left side in FIG. 1 is defined as the left side of themultifunction apparatus 1, and the upper right side is defined as theright side of the multifunction apparatus 1.

As shown in FIG. 1, the multifunction apparatus 1 has a main body 2 anda top cover 3. The main body 2 has a manuscript table 11 on an uppersurface thereof. The manuscript table 11 has a contact glass 16. Thecontact glass 16 is a so-called “platen glass”. The contact glass 16 isformed to have a rectangular shape slightly larger than maximum size ofthe manuscript which the multifunction apparatus 1 can read. A long sideof the contact glass 16 is positioned along the left-right direction ofthe main body 2. The contact glass 16 is used when the manuscript is seton the contact glass 16 and an image is read by moving an aftermentionedimage sensor 20 which constitutes a scanner unit 10.

Further, the main body 2 has the scanner unit 10 below the contact glass16, namely, in an upper part of inner space of the main body 2. Thescanner unit 10 has the image sensor 20, a first carriage 30, a slideshaft 25, a reading transport motor, a flat cable, and the like. Thescanner unit 10 reads an image of the manuscript set on the contactglass 16. The configuration of the scanner unit 10 will be explained indetail hereinafter in reference to the relevant figures.

Then, the main body 2 contains a control section, a facsimile section,an image formation section and the like below the scanner unit 10. Thecontrol section has a CPU, ROM, RAM, and the like. The control sectionplays a central role of the control for the multifunction apparatus 1 torealize a scanner function, a photocopy function, a printer function,and a facsimile function.

The facsimile section transmits the manuscript image read by the scannerunit 10 to the destination desired by a user via a network based on thecontrol by the control section. Further, the facsimile section canreceive facsimile data via the network. The control section controls theimage formation section to print the received facsimile data on a sheetof printing paper or the like in a paper feed cassette 7. That is, themultifunction apparatus 1 realizes the facsimile function by controllingthe scanner unit 10, the facsimile section, and the image formationsection.

The image formation section prints the inputted image data onto theprinting paper transported from the paper feed cassette 7 based on thecontrol by the control section. The multifunction apparatus 1 controlsthe image formation section to process the image data corresponding tothe image read by the scanner unit 10, thereby realizing the photocopyfunction. Further, the multifunction apparatus 1 controls the imageformation section to process the print data inputted via the network,thereby realizing the printer function.

Further, an operation panel 5 and a liquid crystal display 6 areprovided on the upper surface on the front side of the main body 2. Theoperation panel 5 is manipulated to input various instructions to themultifunction apparatus 1. The liquid crystal display 6 displays variouskinds of information about the multifunction apparatus 1 to inform theuser of the contents of the information.

Further, the paper feed cassette 7 is installed to be insertable andremovable through the front surface of the main body 2. The paper feedcassette 7 accommodates sheets of the printing paper as a recordingmedium in a stacked state. The printing paper is used to print the imageformed by the image formation section.

Then, the top cover 3 is provided to be openable and closeable with therear-end edge of the upper surface of the main body 2 as the axis. Whenthe top cover 3 is closed, the top cover 3 covers the upper surface ofthe main body 2, i.e. the manuscript table 11 and the contact glass 16.Therefore, the top cover 3 can fix the manuscript, which is set on thecontact glass 16, at that position.

Further, the top cover 3 has an auto document feeder 4 (ADF). The autodocument feeder 4 is provided on the left side of the top cover 3. Theauto document feeder 4 feeds the manuscripts in a manuscript tray (notshown) one by one consecutively and, after transporting the manuscriptsalong a predetermined transport path, discharges the manuscripts to apaper discharge tray (not shown). The multifunction apparatus 1 can readthe image of the manuscript in a manner in which the scanner unit 10reads the image in the course of transporting the manuscript by the autodocument feeder 4.

Next, referring to FIG. 2, explanations will be made in detail withrespect to a configuration of the scanner unit 10 of the multifunctionapparatus 1. As described above, the scanner unit 10 has the imagesensor 20, the first carriage 30, the slide shaft 25, the readingtransport motor, the flat cable, and the like. The scanner unit 10 isprovided below the contact glass 16 in the upper part of the main body2. Further, in the first embodiment, the portion, in the main body 2, atwhich the scanner unit 10 is provided is parted by a scanner bottomsurface 17 from a portion in which the facsimile section, the imageformation section and the like are accommodated.

The image sensor 20 is configured by a so-called contact image sensor(CIS). The image sensor 20 reads the image of the manuscript positionedon the contact glass 16. The image sensor 20 has a reading surface 21including an imaging element and the like at its upper surfacepositioned on the side of the contact glass 16. The image sensor 20 hasa reading range with a length equivalent to the short side of themaximum manuscript size in the main scanning direction, i.e. thefront-rear direction with respect to the main body 2. Further, the imagesensor 20 is formed to have an approximately cuboid shape and to extendin the main scanning direction. The image sensor 20 is contained in anaftermentioned sensor container 31 of the first carriage 30.

As shown in FIG. 2, the slide shaft 25 is a shaft member having acircular rod form. The slide shaft 25 is provided over or above thescanner bottom surface 17 to extend toward the left and right directionsof the main body 2. The slide shaft 25 supports the image sensor 20 tobe slidable in the left-right direction via the first carriage 30. Then,based on the driving control by the control section, the readingtransport motor can slide the image sensor 20 which is installed on thefirst carriage 30 along the slide shaft 25 via a driving forcetransmission mechanism such as a pulley belt mechanism and the like.

Then, in the multifunction apparatus 1, the image sensor 20 is usuallylocated in a so-called home position, i.e. a standby position S underthe left end portion of the contact glass 16. As shown in FIGS. 2 and 5,the image sensor 20 can slide along the lower surface of the contactglass 16 from the standby position S up to a position at a distanceequivalent to the long side of the maximum manuscript size (to bereferred to as “terminal position T” hereinbelow).

The image sensor 20 reads an image from the manuscript set on thecontact glass 16 when the image sensor 20 is moved between the standbyposition S and the terminal position T along a secondary scanningdirection parallel to the left-right direction of the multifunctionapparatus 1. Therefore, as shown in FIG. 1, the scanner unit 10 has themaximum reading range R corresponding to the maximum-sized manuscriptand can read an image of any manuscript which is not larger than themaximum manuscript size.

Next, referring to FIGS. 3 to 5, explanations will be made in detailwith respect to a configuration of the first carriage 30 supporting theimage sensor 20 in the scanner unit 10 according to the firstembodiment. As described above, the first carriage 30 supports the imagesensor 20 from below and supports the image sensor 20 to be slidablealong the slide shaft 25 in the secondary scanning direction.

As shown in FIGS. 3 and 4, the first carriage 30 includes the sensorcontainer 31, and spring attachment portions 32. The first carriage 30extends in the front-rear direction of the multifunction apparatus 1.The sensor container 31 is formed to have a recess which is open to thecontact glass 16, and configured as a groove extending along thefront-rear direction of the multifunction apparatus 1. The sensorcontainer 31 contains the image sensor 20 so that the reading surface 21of the image sensor 20 faces upward, i.e. toward the contact glass 16.The sensor container 31 supports the image sensor 20 from below.

The spring attachment portions 32 are formed on the end portions in thelongitudinal direction of the first carriage 30 positioned on the frontside of the multifunction apparatus 1. The spring attachment portions 32are configured to be capable of attachment of a holder member 35 andsprings 36. As shown in FIGS. 3 to 5, the spring attachment portions 32are adjacent to the sensor container 31 and face each other in thesecondary scanning direction of the multifunction apparatus 1 so thatthe sensor container 31 is sandwiched therebetween.

As shown in FIG. 4, the sensor container 31 has an opening 31A on a sideof an end portion of the first carriage 30. The opening 31A is formed topenetrate the bottom of the sensor container 31 which is positioned onthe side of the end portion provided with the spring attachment portions32 within a certain range, i.e. an area from the central portion up tothe end portion side in the longitudinal direction. Therefore, the endportion of the image sensor 20 contained in the sensor container 31 ismovable downward below the first carriage 30 via the opening 31A.

As shown in FIGS. 4 and 5, the holder member 35 supports the imagesensor 20 contained in the sensor container 31 from below. The holdermember 35 holds the springs 36 between the holder member 35 and thespring attachment portions 32. The holder member 35 has a sensor supportportion 35A, biased portions 35B, and locking hooks 35C.

As shown in FIG. 5, similar to the sensor container 31, the sensorsupport portion 35A is formed to have a recess which is open upward. Thesensor support portion 35A supports the lower surface of the imagesensor 20 contained in the sensor container 31. Further, under acondition that the holder member 35 is attached to the sensor container31, the sensor support portion 35A traverses the opening 31A in thesecondary scanning direction at the position of forming the springattachment portions 32.

The biased portions 35B are formed to extend horizontally in outwarddirections with respect to the sensor support portion 35A from the twoupper ends of the sensor support portion 35A formed to have a recesswhich is open upward. The biased portions 35B retain the end portions ofthe springs 36 attached to the spring attachment portions 32,respectively. As shown in FIG. 5, under a condition that the holdermember 35 is attached to the first carriage 30, the biased portions 35Bare positioned above the spring attachment portions 32, respectively.The biased portions 35B are biased upward by the springs 36 attached tothe spring attachment portions 32, respectively.

Further, the locking hooks 35C are hooks extending downward from the endedges of the respective biased portions 35B positioned outside of thesensor support portion 35A. The locking hooks 35C have claw portions atthe lower end portions to project toward outside, respectively. Then, byengagement with engagement holes 31B formed in the first carriage 30,the locking hooks 35C fulfill the function of retaining the holdermember 35 to prevent the holder member 35 from coming off the firstcarriage 30.

As shown in FIG. 5, the engagement holes 31B are formed by cutting awaythe lower portions of the side walls of the first carriage 30 on theleft and right at the spring attachment portions 32, respectively. Undera condition that the holder member 35 is attached to the first carriage30, the claw portions of the locking hooks 35C enter into the engagementholes 31B. Therefore, if the holder member 35 moves upward by thebiasing force of the springs 36, then the claw portions of the lockinghooks 35C come into contact with the upper ends of the engagement holes31B. By these contacts, the holder member 35 is retained in placewithout coming off the first carriage 30, and thereby it is possible toprevent loss of the holder member 35.

The springs 36 are provided between the biased portions 35B of theholder member 35 and the spring attachment portions 32, respectively.The upper ends of the springs 36 make contact with the lower surfaces ofthe biased portions 35B. The lower ends of the springs 36 are retainedon the spring attachment portions 32. As shown in FIG. 5, the upper endsof the springs 36 are positioned below the contact glass 16 and abovethe lower surface of the image sensor 20 contained in the sensorcontainer 31. Further, the spring attachment portions 32 retaining thelower ends of the springs 36 are positioned above the lower surface ofthe image sensor 20 in the sensor container 31. Therefore, between thebiased portions 35B of the holder member 35 and the spring attachmentportions 32, the springs 36 can bias the image sensor 20 along with theholder member 35 upward to the contact glass 16.

As explained above, in the multifunction apparatus 1 of the firstembodiment, on the side of the end portion of the first carriage 30, thetwo biased portions 35B constituting the holder member 35 are adjacentto the reading surface 21 of the image sensor 20 in the sensor container31 in the left-right direction. Then, between the respective biasedportions 35B and spring attachment portions 32, the springs 36 bias thebiased portions 35B of the holder member 35 upward. Here, the imagesensor 20 is supported from below by the sensor support portion 35A ofthe holder member 35. Therefore, the image sensor 20 is biased towardthe contact glass 16 by the biasing force of the springs 36 exerted onthe biased portions 35B of the holder member 35.

Further, as shown in FIG. 3, when viewed from upside of the readingsurface 21 of the image sensor 20 in the sensor container 31, the biasedportions of the present invention are adjacent to the reading surface21. That is, as long as this condition is satisfied, the biased portionsmay be positioned at any position in the up-down direction with respectto the reading surface 21 of the image sensor 20. For example, as longas the above condition is satisfied, the biased portions may bepositioned either above the reading surface 21 or below the readingsurface 21. Further, the biased portions may also be at the same heightwith the reading surface 21.

As shown in FIGS. 3 to 5, in the first embodiment, the springs 36 arenot ever positioned between the lower surface of the image sensor 20 andthe sensor container 31. Therefore, it is possible for the multifunctionapparatus 1 to reduce the vertical dimension of the image sensor 20 andfirst carriage 30. Further, the springs 36 bias the image sensor 20 tothe contact glass 16 via the biased portions 35B adjacent to the readingsurface 21 of the image sensor 20 in the secondary scanning direction.Therefore, the multifunction apparatus 1 can utilize the space in thefirst carriage 30 adjacent to the sensor container 31 in the secondaryscanning direction to bias the image sensor 20 toward the contact glass16. That is, it is possible for the multifunction apparatus 1 tofacilitate miniaturization of the apparatus in the vertical directionand to bias the image sensor 20 toward the contact glass 16.

Further, as shown in FIG. 5, the two biased portions 35B of the holdermember 35 are adjacent to the reading surface 21 of the image sensor 20in the sensor container 31 in the left-right direction. The two biasedportions 35B are biased upward by the springs 36. That is, according tothe multifunction apparatus 1, it is possible to balance the biasingforce of the springs 36 for the image sensor 20 in the left-rightdirection. Therefore, it is possible to bias the reading surface 21 ofthe image sensor 20 toward the contact glass 16 in an appropriate state,i.e., being kept in a horizontal state.

Second Embodiment

Next, referring to the relevant figures, explanations will be made indetail with respect to a second embodiment. Further, a multifunctionapparatus 1 according to the second embodiment basically has the sameconfiguration with the multifunction apparatus 1 according to the firstembodiment, but differs in the configurations of the carriage and theholder member of the scanner unit 10. Hence, explanations will beomitted for the same configuration as in the first embodiment.

Referring to FIGS. 6 and 7, explanations will be made in detail withrespect to configurations of a carriage (to be referred to as a “secondcarriage 40” below) and a holder member 45 according to the secondembodiment. Similar to the aforementioned first carriage 30, the secondcarriage 40 supports the image sensor 20 from below and supports theimage sensor 20 to be slidable along the slide shaft 25 in the secondaryscanning direction.

As shown in FIGS. 6 and 7, the second carriage 40 includes a sensorcontainer 41, and a spring fitting portion 42. The second carriage 40extends in the front-rear direction of the multifunction apparatus 1.The sensor container 41 has an opening 41A. The sensor container 41 hasthe same configuration with the sensor container 31 of the firstcarriage 30 in the first embodiment. Accordingly, explanations will beomitted for the configurations of the sensor container 41 and theopening 41A.

Further, the spring fitting portion 42 is formed in the end portion inthe longitudinal direction of the second carriage 40 positioned on thefront side of the multifunction apparatus 1. The spring fitting portion42 is configured to be capable of attachment of the holder member 45 anda spring 46. As shown in FIG. 7, the spring fitting portion 42 isadjacent to the left side of the sensor container 41 in the secondaryscanning direction of the multifunction apparatus 1.

Similar to the first embodiment, the holder member 45 in the secondembodiment supports the image sensor 20 contained in the sensorcontainer 41 from below. The holder member 45 holds the spring 46between the holder member 45 and the spring fitting portion 42. Here, asshown in FIGS. 6 and 7, the holder member 45 has a sensor supportportion 45A, a biased portion 45B, a locking hook 45C, and a revolvingretainment portion 45D. Since the sensor support portion 45A has thesame configuration with the aforementioned sensor support portion 35A ofthe first carriage 30, the explanation of which will be omitted.

In the holder member 45 according to the second embodiment, the biasedportion 45B is formed to extend horizontally in an outward directionwith respect to the sensor support portion 45A from the left upper endof the sensor support portion 45A formed to have a recess which is openupward. The biased portion 45B retains the end portion of the spring 46attached to the spring fitting portion 42. As shown in FIG. 7, under acondition that the holder member 45 is attached to the second carriage40, the biased portion 45B is positioned above the spring fittingportion 42. The biased portion 45B is biased upward by the spring 46attached to the spring fitting portion 42.

Further, the locking hook 45C is a hook extending downward from the leftend edge of the biased portion 45B. The locking hook 45C has a clawportion at the lower end portion to project toward outside. Then, byengagement with an engagement hole 41B formed in the second carriage 40,the locking hook 45C fulfills the function of retaining the holdermember 45 to prevent the holder member 45 from coming off the secondcarriage 40.

As shown in FIG. 7, the revolving retainment portion 45D is formed toextend in an outward direction with respect to the sensor supportportion 45A from the right upper end of the sensor support portion 45A.The revolving retainment portion 45D retains the holder member 45 sothat the holder member 45 can revolve upward with respect to the secondcarriage 40 about the revolving retainment portion 45D.

The spring 46 is provided between the biased portion 45B of the holdermember 45 and the spring fitting portion 42. The upper end of the spring46 makes contact with the lower surface of the biased portion 45B. Thelower end of the spring 46 is retained on the spring fitting portion 42.As shown in FIG. 7, the upper end of the spring 46 is positioned belowthe contact glass 16 and above the lower surface of the image sensor 20contained in the sensor container 41. Further, the spring fittingportion 42 retaining the lower end of the spring 46 is positioned abovethe lower surface of the image sensor 20 in the sensor container 41.Accordingly, between the biased portion 45B of the holder member 45 andthe spring fitting portion 42, the spring 46 can bias the image sensor20 upward along with the holder member 45.

As explained above, in the multifunction apparatus 1 of the secondembodiment, on the end portion side of the second carriage 40, thebiased portion 45B of the holder member 45 is adjacent to left side ofthe reading surface 21 of the image sensor 20 in the sensor container41. Then, between the biased portion 45B and spring fitting portion 42,the spring 46 biases the biased portion 45B of the holder member 45upward. Further, the holder member 45 is retained so that the holdermember 45 can revolve about the revolving retainment portion 45D by therevolving retainment portion 45D formed in the right-side portion of thesensor support portion 45A. Here, the image sensor 20 is supported frombelow by the sensor support portion 45A of the holder member 45.Therefore, the image sensor 20 is biased toward the contact glass 16 bythe biasing force of the spring 46 exerted on the biased portion 45B ofthe holder member 45.

As shown in FIG. 7, also in the second embodiment, the spring 46 is notpositioned between the lower surface of the image sensor 20 and thesensor container 41. Accordingly, it is possible for the multifunctionapparatus 1 to reduce the vertical dimension of the image sensor 20 andsecond carriage 40. Further, the spring 46 biases the image sensor 20 tothe contact glass 16 via the biased portion 45B adjacent to the readingsurface 21 of the image sensor 20 in the secondary scanning direction.Accordingly, the multifunction apparatus 1 can utilize the space in thesecond carriage 40 adjacent to the sensor container 41 in the secondaryscanning direction to bias the image sensor 20 toward the contact glass16. That is, it is possible for the multifunction apparatus 1 tofacilitate miniaturization of the apparatus in the vertical directionand to bias the image sensor 20 toward the contact glass 16.

Third Embodiment

Next, referring to the relevant figures, explanations will be made indetail with respect to a third embodiment. Further, a multifunctionapparatus 1 according to the third embodiment basically has the sameconfiguration with the multifunction apparatus 1 according to the firstembodiment or the second embodiment, but differs in the configurationsof the carriage and the holder member of the scanner unit 10. Hence,explanations will be made only for those differences in reference to therelevant figures, but omitted for the same configuration as in the firstembodiment or the second embodiment.

Referring to FIG. 8 and the like, explanations will be made in detailwith respect to configurations of a carriage (to be referred to as a“third carriage 50” below), a first holder member 55 and a second holdermember 56 according to the third embodiment. Similar to theaforementioned first carriage 30 and second carriage 40, the thirdcarriage 50 supports the image sensor 20 from below and supports theimage sensor 20 to be slidable along the slide shaft 25 in the secondaryscanning direction.

As shown in FIG. 8, the third carriage 50 includes a sensor container51, first spring attachment portions 52, and second spring attachmentportions 53. The third carriage 50 extends in the front-rear directionof the multifunction apparatus 1. Further, the sensor container 51 hasthe same configuration with the sensor container 31 of the firstcarriage 30 in the first embodiment. Accordingly, explanations will beomitted for the configuration of the sensor container 51.

Further, the first spring attachment portions 52 are formed on one endportion in the longitudinal direction of the third carriage 50positioned on the front side of the multifunction apparatus 1. The firstspring attachment portions 52 are configured to be capable of attachmentof the first holder member 55 and springs 57. As shown in FIG. 8, thefirst spring attachment portions 52 are adjacent to the sensor container51 and face each other in the secondary scanning direction of themultifunction apparatus 1 so that the sensor container 51 is sandwichedtherebetween.

Further, the second spring attachment portions 53 are formed on theother end portion in the longitudinal direction of the third carriage 50positioned on the rear side of the multifunction apparatus 1. The secondspring attachment portions 53 are configured to be capable of attachmentof the second holder member 56 and other springs 57. As shown in FIG. 8,the second spring attachment portions 53 are adjacent to the sensorcontainer 51 and face each other in the secondary scanning direction ofthe multifunction apparatus 1 so that the sensor container 51 issandwiched therebetween.

In the third embodiment, the first holder member 55 and the secondholder member 56 support the image sensor 20 contained in the sensorcontainer 51 from below on both end portions in the longitudinaldirection of the image sensor 20, respectively. The first holder member55 holds the springs 57 between the first spring attachment portions 52and the first holder member 55 and the second holder member 56 holds thesprings 57 between the second spring attachment portions 53 and thesecond holder member 56.

Similar to the holder member 35 according to the first embodiment, thefirst holder member 55 has a sensor support portion, biased portions55A, and locking hooks. Further, also similar to the holder member 35according to the first embodiment, the second holder member 56 has asensor support portion, biased portions 56A, and locking hooks.

Since the first holder member 55 and the second holder member 56 havethe same configuration with the aforementioned holder member 35according to the first embodiment, their explanations will be omitted.Further, the aspect of attachment of the first holder member 55 to thefirst spring attachment portions 52, as well as the aspect of attachmentof the second holder member 56 to the second spring attachment portions53, is the same as that of the attachment of the holder member 35 to thespring attachment portions 32 as explained in the first embodiment inreference to FIG. 5. Therefore, the explanations for those aspects willalso be omitted.

As explained above, in the multifunction apparatus 1 of the thirdembodiment, on both end portion sides in the main scanning direction ofthe third carriage 50, the biased portions 55A of the first holdermember 55 and the biased portions 56A of the second holder member 56 areadjacent to the reading surface 21 of the image sensor 20 in the sensorcontainer 51 in the left-right direction. Then, between the respectivebiased portions 55A and first spring attachment portions 52, the springs57 bias the biased portions 55A of the first holder member 55 upward.Further, between the respective biased portions 56A and second springattachment portions 53, the other springs 57 bias the biased portions56A of the second holder member 56 upward.

Here, the image sensor 20 is supported from below by the sensor supportportions of the first holder member 55 and the second holder member 56.Accordingly, the image sensor 20 is biased toward the contact glass 16by the biasing force of the springs 57 exerted on the first holdermember 55 and the second holder member 56. That is, in the thirdembodiment, in both end portions of the image sensor 20 in the mainscanning direction, the biasing force of the springs 57 is exerted onthe image sensor 20 via the first holder member 55 and the second holdermember 56. Therefore, it is possible for the multifunction apparatus 1to bias the image sensor 20 toward the contact glass 16 in the optimumstate, i.e., being kept in a horizontal state with respect to the mainscanning direction of the image sensor 20.

In the third embodiment, the springs 57 are not positioned between thelower surface of the image sensor 20 and the sensor container 51.Accordingly, it is possible for the multifunction apparatus 1 to reducethe vertical dimension of the image sensor 20 and third carriage 50.Further, the springs 57 bias the image sensor 20 to the contact glass 16via the biased portions 55A and biased portions 56A adjacent to thereading surface 21 of the image sensor 20 in the secondary scanningdirection. Accordingly, the multifunction apparatus 1 can utilize thespace in the third carriage 50 adjacent to the sensor container 51 inthe secondary scanning direction to bias the image sensor 20 toward thecontact glass 16. That is, it is possible for the multifunctionapparatus 1 to facilitate miniaturization of the apparatus in thevertical direction while biasing the image sensor 20 toward the contactglass 16.

Further, as shown in FIG. 8, the two biased portions 55A of the firstholder member 55 and the two biased portions 56A of the second holdermember 56 are adjacent to the reading surface 21 of the image sensor 20in the sensor container 51 in the left-right direction, respectively.The two biased portions 55A and the two biased portions 56A are biasedupward by the springs 57, respectively. That is, according to themultifunction apparatus 1, it is possible to balance the biasing forceof the springs 57 for the image sensor 20 in the left-right direction.Accordingly, it is possible to bias the reading surface 21 of the imagesensor 20 toward the contact glass 16 in an appropriate state, i.e.,being kept in a horizontal state also with respect to the secondaryscanning direction.

Fourth Embodiment

Next, referring to the relevant figures, explanations will be made indetail with respect to a fourth embodiment. A multifunction apparatus 1according to the fourth embodiment basically has the same configurationwith the multifunction apparatus 1 according to any of the firstembodiment to the third embodiment, but differs in the configurations ofthe carriage and the holder member of the scanner unit 10. Hence,explanations will be made only for those differences in reference to therelevant figures, but omitted for the same configuration as in any ofthe first embodiment to the third embodiment.

Referring to FIG. 9 and the like, explanations will be made in detailwith respect to configurations of a carriage (to be referred to as a“fourth carriage 60” below) and a holder member 65 according to thefourth embodiment. Similar to the aforementioned first carriage 30,second carriage 40 and third carriage 50, the fourth carriage 60supports the image sensor 20 from below. The fourth carriage 60 supportsthe image sensor 20 to be slidable along the slide shaft 25 in thesecondary scanning direction.

As shown in FIG. 9, the fourth carriage 60 includes a sensor container61 and spring attachment portions 62. The fourth carriage 60 extends inthe front-rear direction of the multifunction apparatus 1. Further, thesensor container 61 has the same configuration with the sensor container31 of the first carriage 30 in the first embodiment. Accordingly,explanations will be omitted for the configuration of the sensorcontainer 61.

Further, the spring attachment portions 62 are formed in the centralportion in the longitudinal direction of the fourth carriage 60. Thespring attachment portions 62 are configured to be capable of attachmentof the holder member 65 and springs 66. As shown in FIG. 9, the springattachment portions 62 are adjacent to the sensor container 61 and faceeach other in the secondary scanning direction of the multifunctionapparatus 1 so that the sensor container 61 is sandwiched therebetween.

In the fourth embodiment, the holder member 65 supports the image sensor20 contained in the sensor container 61 from below on the centralportion in the longitudinal direction of the image sensor 20. The holdermember 65 holds the springs 66 between the holder member 65 and thespring attachment portions 62. Similar to the holder member 35 accordingto the first embodiment, the holder member 65 has a sensor supportportion, biased portions 65A, and locking hooks.

Since the holder member 65 has the same configuration with theaforementioned holder member 35 according to the first embodiment, theexplanation of which will be omitted. Further, the aspect of attachmentof the holder member 65 to the spring attachment portions 62 is the sameas that of attachment of the holder member 35 in the first embodiment.Therefore, the explanation for that aspect will also be omitted.

As explained above, in the multifunction apparatus 1 of the fourthembodiment, in the central portion in the main scanning direction of thefourth carriage 60, the biased portions 65A of the holder member 65 areadjacent to the reading surface 21 of the image sensor 20 in the sensorcontainer 61 in the left-right direction. Then, between the respectivebiased portions 65A and spring attachment portions 62, the springs 66bias the biased portions 65A of the holder member 65 upward. The imagesensor 20 is supported from below by the sensor support portion of theholder member 65. Accordingly, the image sensor 20 is biased toward thecontact glass 16 by the biasing force of the springs 66 exerted on theholder member 65. That is, in the fourth embodiment, in the centralportion in the main scanning direction of the image sensor 20, thebiasing force of the springs 66 is exerted on the image sensor 20 viathe holder member 65. Therefore, it is possible for the multifunctionapparatus 1 with a small number of components to bias the image sensor20 toward the contact glass 16 while keeping the same in a comparativelyhorizontal state.

Also in the fourth embodiment, the springs 66 are not positioned betweenthe lower surface of the image sensor 20 and the sensor container 61.Accordingly, it is possible for the multifunction apparatus 1 to reducethe vertical dimension of the image sensor 20 and fourth carriage 60.Further, the springs 66 bias the image sensor 20 to the contact glass 16via the biased portions 65A adjacent to the reading surface 21 of theimage sensor 20 in the secondary scanning direction. Accordingly, themultifunction apparatus 1 can utilize the space in the fourth carriage60 adjacent to the sensor container 61 in the secondary scanningdirection to bias the image sensor 20 toward the contact glass 16. Thatis, it is possible for the multifunction apparatus 1 to facilitateminiaturization of the apparatus in the vertical direction and to biasthe image sensor 20 toward the contact glass 16.

Further, as shown in FIG. 9, the two biased portions 65A of the holdermember 65 are adjacent to the reading surface 21 of the image sensor 20in the sensor container 61 in the left-right direction. The two biasedportions 65A are biased upward by the springs 66. That is, according tothe multifunction apparatus 1, it is possible to balance the biasingforce of the springs 66 for the image sensor 20 in the left-rightdirection. Accordingly, it is possible to bias the reading surface 21 ofthe image sensor 20 toward the contact glass 16 in an appropriate state,i.e., being kept in a horizontal state with respect to the secondaryscanning direction.

Fifth Embodiment

Next, referring to the relevant figures, explanations will be made indetail with respect to a fifth embodiment. A multifunction apparatus 1according to the fifth embodiment basically has the same configurationwith the multifunction apparatus 1 according to any of the firstembodiment to the fourth embodiment, but differs in the configurationsof the carriage and the holder member of the scanner unit 10. Hence,explanations will be made only for those differences in reference to therelevant figures, but omitted for the same configuration as in any ofthe first embodiment to the fourth embodiment.

Referring to FIGS. 10 and 11, explanations will be made in detail withrespect to configurations of a carriage (to be referred to as a “fifthcarriage 70” below) and a holder member 75 according to the fifthembodiment. Similar to the aforementioned first carriage 30, the fifthcarriage 70 supports the image sensor 20 from below. The fifth carriage70 supports the image sensor 20 to be slidable along the slide shaft 25in the secondary scanning direction.

As shown in FIGS. 10 and 11, the fifth carriage 70 includes a sensorcontainer 71 and spring attachment portions 72. The fifth carriage 70extends in the front-rear direction of the multifunction apparatus 1.The sensor container 71 has an opening 71A and engagement holes 71B. Thesensor container 71 has the same configuration with the sensor container31 of the first carriage 30 in the first embodiment. Accordingly,explanations will be omitted for the configuration of the sensorcontainer 71.

Further, the spring attachment portions 72 are formed in an end portionin the longitudinal direction of the fifth carriage 70 positioned on thefront side of the multifunction apparatus 1. The spring attachmentportions 72 are configured to be capable of attachment of the holdermember 75 and springs 76. As shown in FIGS. 10 and 11, the springattachment portions 72 are adjacent to the sensor container 71 and faceeach other in the secondary scanning direction of the multifunctionapparatus 1 so that the sensor container 71 is sandwiched therebetween.

In the fifth embodiment, the holder member 75 supports the image sensor20 contained in the sensor container 71 from below in the front endportion in the longitudinal direction of the image sensor 20. The holdermember 75 holds the springs 76 between the holder member 75 and thespring attachment portions 72. As shown in FIG. 11, the holder member 75has a sensor support portion 75A, biased portions 75B, locking hooks75C, and spacer ribs 75D.

Since the sensor support portion 75A, the biased portions 75B and thelocking hooks 75C of the holder member 75 have the same configurationswith the sensor support portion 35A, the biased portions 35B and thelocking hooks 35C of the aforementioned holder member 35 according tothe first embodiment, respectively, their explanations will be omitted.Further, the aspect of attachment of the holder member 75 to the springattachment portions 72 is the same as that of attachment of the holdermember 35 in the first embodiment. Accordingly, the explanation for thataspect will also be omitted.

As shown in FIGS. 10 and 11, the spacer ribs 75D are ribs which projectsupward to the contact glass 16 on the upper surfaces of the biasedportions 75B. If the holder member 75 moves upward due to the biasingforce of the springs 76, then the upper ends of the spacer ribs 75D comeinto contact with the lower surface of the contact glass 16. That is,according to the multifunction apparatus 1 of the fifth embodiment, byvirtue of the spacer ribs 75D, it is possible to keep a distance betweenthe reading surface 21 of the image sensor 20 retained by the holdermember 75 and the lower surface of the contact glass 16 constantly,based on the projection amount of the spacer ribs 75D. As a result, themultifunction apparatus 1 can properly maintain the distance between thereading surface 21 of the image sensor 20 and a manuscript on thecontact glass 16, and thereby it is possible to maintain the readingquality of the scanner unit 10.

The springs 76 are provided between the biased portions 75B of theholder member 75 and the spring attachment portions 72, respectively.The upper ends of the springs 76 make contact with the lower surfaces ofthe biased portions 75B. The lower ends of the springs 76 are retainedon the spring attachment portions 72. As shown in FIG. 11, the upperends of the springs 76 are positioned below the contact glass 16 andabove the lower surface of the image sensor 20 contained in the sensorcontainer 71. Further, the spring attachment portions 72 retaining thelower ends of the springs 76 are positioned above the lower surface ofthe image sensor 20 in the sensor container 71. Accordingly, between thebiased portions 75B of the holder member 75 and the spring attachmentportions 72, the springs 76 can bias the image sensor 20 upward alongwith the holder member 75.

As explained above, in the multifunction apparatus 1 of the fifthembodiment, on the end portion side of the fifth carriage 70, the twobiased portions 75B constituting the holder member 75 are adjacent tothe reading surface 21 of the image sensor 20 in the sensor container 71in the left-right direction. Then, between the respective biasedportions 75B and spring attachment portions 72, the springs 76 bias thebiased portions 75B of the holder member 75 upward. Here, the imagesensor 20 is supported from below by the sensor support portion 75A ofthe holder member 75. Accordingly, the image sensor 20 is biased towardthe contact glass 16 by the biasing force of the springs 76 exerted onthe biased portions 75B of the holder member 75.

As shown in FIG. 11, in the fifth embodiment, the springs 76 are notpositioned between the lower surface of the image sensor 20 and thesensor container 71. Therefore, it is possible for the multifunctionapparatus 1 to reduce the vertical dimension of the image sensor 20 andfifth carriage 70. Further, the springs 76 bias the image sensor 20 tothe contact glass 16 via the biased portions 75B adjacent to the readingsurface 21 of the image sensor 20 in the secondary scanning direction.Therefore, the multifunction apparatus 1 can utilize the space in thefifth carriage 70 adjacent to the sensor container 71 in the secondaryscanning direction to bias the image sensor 20 toward the contact glass16. That is, it is possible for the multifunction apparatus 1 tofacilitate miniaturization of the apparatus in the vertical directionand to bias the image sensor 20 toward the contact glass 16.

Further, as shown in FIGS. 10 and 11, the two biased portions 75B of theholder member 75 are adjacent to the reading surface 21 of the imagesensor 20 in the sensor container 71 in the left-right direction. Thetwo biased portions 75B are biased upward by the springs 76. Further,the biased portions 75B have the spacer ribs 75D on their uppersurfaces, respectively. Therefore, according to the multifunctionapparatus 1, it is possible to balance the biasing force of the springs76 for the image sensor 20 in the left-right direction. Further, byvirtue of the spacer ribs 75D, it is possible for the multifunctionapparatus 1 to keep a distance between the reading surface 21 of theimage sensor 20 and the lower surface of the contact glass 16constantly. Accordingly, it is possible to bias the reading surface 21of the image sensor 20 toward the contact glass 16 in an appropriatestate, i.e., being kept in a horizontal state.

In the fifth embodiment, the holder member 75 is attached to the frontend portion of the fifth carriage 70 and the spacer ribs 75D areprovided on the upper surfaces of the biased portions 75B of the holdermember 75. However, a spacer rib may also be provided on the uppersurface of the biased portion 45B of the holder member 45 in the secondembodiment. Further, spacer ribs may also be provided on the uppersurfaces of the biased portions 55A of the first holder member 55 andthe biased portions 56A of the second holder member 56 in the thirdembodiment, respectively. Furthermore, spacer ribs may also be providedon the upper surfaces of the biased portions 65A of the holder member 65in the fourth embodiment. In any of these cases, by virtue of the spacerribs, it is possible to maintain a distance between the reading surface21 of the image sensor 20 and the lower surface of the contact glass 16constantly.

Based on the embodiments, the present invention was describedhereinabove. However, the present invention is not limited to theembodiments described above, but can undergo various modifications andchanges without departing from the gist and scope of the presentinvention. For example, in the above embodiments, an example is shown bythe multifunction apparatus 1 having a scanner function, a photocopyfunction, a printer function, and a facsimile function. However, thepresent invention is not limited to this aspect. It is possible to applythe present invention to any scanner apparatuses or photocopy machineswhich at least have a scanner unit of the flatbed type.

Further, in the above embodiments, the biased portions are positioned tobe adjacent to the reading surface of the image sensor in the secondaryscanning direction. However, the present invention is not limited tothis aspect. That is, the biased portions may alternatively bepositioned to be adjacent to the reading surface of the image sensor inthe main scanning direction.

Further, in the above embodiments, the biased portions of the holdermember are biased upward by the springs so as to bias the image sensorsupported by the holder member toward the contact glass. However, thepresent invention is not limited to this aspect. For example, in theupper portions of side surfaces of the image sensor, biased portions maybe formed to extend horizontally in outward directions from the imagesensor. In this case, by exerting the biasing force of the springs onthe biased portions formed integrally with the image sensor, the imagesensor may also be biased toward the contact glass.

That is, the biased portions of the present invention may be memberswhich receive the biasing force of a biasing member at a positionadjacent to the reading surface of the image sensor, and which exert thebiasing force to bias the image sensor toward the contact glass.Accordingly, as described above, the biased portions of the presentinvention include those formed integrally with the image sensor.Further, as in each of the embodiments described above, it is a matterof course that the biased portions also include those formed in anothermembers separate from the image sensor.

In the above embodiments, the spring attachment portions are formed inthe end portion(s) or the central portion in the longitudinal directionof the carriage so as to attach the holder member and the springs. Byvirtue of this configuration, the image sensor 20 is biased toward thecontact glass 16. However, the present invention is not limited to thisaspect. For example, it may alternatively be configured that the imagesensor 20 is biased toward the contact glass 16 by forming the springattachment portions in both end portions and the central portion in thelongitudinal direction of the carriage to attach the holder members andthe springs in those three portions.

What is claimed is:
 1. An image reading apparatus comprising: a contactglass having an upper surface and a lower surface which are opposite toeach other, the upper surface being configured to support a manuscriptthereon; an image sensor unit disposed below the contact glass andincluding: an image sensor extending in a first direction and configuredto read an image of the manuscript supported on the upper surface of thecontact glass, the image sensor having an upper surface facing the lowersurface of the contact glass, and a lower surface opposite to the uppersurface; and a retainment portion having a pivot axis which extends inthe first direction and about which the image sensor unit is pivotable,a carriage configured to carry the image sensor unit in a seconddirection perpendicular to the first direction; a guide member extendingin the second direction and configured to guide the carriage in thesecond direction; and a spring having a first end received by thecarriage, and a second end configured to bias the image sensor unittoward the contact glass such that the image sensor unit pivots aboutthe pivot axis of the retainment portion, wherein the pivot axis of theretainment portion and at least a portion of the spring are offset fromthe image sensor in the second direction, and located below the uppersurface of the image sensor and above the lower surface of the imagesensor.
 2. The image reading apparatus according to claim 1, wherein thespring is closer to one end of the image sensor in the first directionthan to the guide member.
 3. The image reading apparatus according toclaim 1, wherein the spring is a coil spring.
 4. The image readingapparatus according to claim 1, wherein the image sensor unit furtherincludes a biased portion in contact with the second end of the spring,the biased portion being offset in the second direction from the imagesensor.
 5. The image reading apparatus according to claim 1, wherein thepivot axis of the retainment portion and the at least a portion of thespring are located opposite to each other in the second directionrelative to the image sensor.
 6. The image reading apparatus accordingto claim 1, wherein the image sensor unit further includes a holdermember which holds the image sensor and includes the retainment portion,and the spring is configured to bias the holder member toward thecontact glass such that the holder member pivots about the pivot axis ofthe retainment portion.
 7. The image reading apparatus according toclaim 1, wherein the spring extends in a vertical direction.
 8. Theimage reading apparatus according to claim 1, wherein the first end andthe second end of the spring are located below the upper surface of theimage sensor and above the lower surface of the image sensor.
 9. Theimage reading apparatus according to claim 1, wherein an entirety of thespring is offset from the image sensor in the second direction.